Rotary dry shaver



Jan. 10, 1950 w. L. L. vlvlE ErAl. 2,494,464

ROTARY DRY SHAVER Filed May 4, 1946 manufacture.

Patented Jan. l0, 1950 UNITED STATES PATENT OFFICE ROTARY DRY SHAVERConn., as trustee Application May 4, 1946, Serial No. 667,392 In theNetherlands January 13, 1942 Section 1, Public Law 690, August 8, 1946Patent expires January 13, 19.62

6 Claims.

This invention relates to a cutting plate for dry-shaving apparatushaving a rotary cutting member, which cutting plate possesses an annularand apertured running surface for the cutting member which surface issupported both at the inner and outer edges. It is known in the dryshaver art that in shaving by means of dryshaving apparatus the hairsare cut more rapidly and shorter as the cutting plate is made thinner atthe running surface of the cutting member. Although very smallthicknesses of the material have been proposed theoretically for thispurpose it has been found in practice that a deiinite limit cannot beexceeded in conjunction with reasonable conditions as regards solidity,life and For this reason the thickness of the cutting plate at therunning surface amounts it about 0.08 mm. in commercial apparatus of theabove-mentioned kind of shaving apparatus. The invention is based on therealisation that in satisfying the above-mentioned conditions thecutting plate may be made thinner locally if on the other handstrengthenings are provided at other points.

To this end, according to the invention, the inner edge of the runningsurface of a cutting plate, which has an annular apertured runningsurface for a rotary cutting member which surface is supported both atthe inner and at the outer edges, is thinner than the outer edge.

An object of the invention is to make the annular running surface forthe cutting member at the inner edge thinner and at the outer edgethicker than it has hitherto been customary in practice with suchcutting plates. Since the running surface of these cutting platesgenerally bears at the outer edge on the housing of the shavingapparatus, and the support at the inner edge is constituted by a memberof the cutting plate itself solely providing for the initial relation,for instance a plate-shaped or a cup-shaped part of the cutting platewith or without a bottom, a sufficiently solid construction of thecutting plate for permitting an inner part of the running surface whichis thinner than normal is obtained by making use of the outer part ofthe running surface which is thicker than normal.

As a result of the use of a thinner annular central part of the cuttingplate according to the invention the hairs may be cut shorter and morerapidly than by means of a conventional cutting plate of this type. Inthis case the thicker outer edge of the running surface acts as a roughshaving device, by which the hairs are cut somewhat shorter than bymeans of a normal cutting plate. However, this constitutes by no means adrawback, since it has been found in practice that when using the usualcutting plate having the same thickness throughout the hairs are notdirectly cut to a minimum length but stepwise to a smaller length ineach instance.

The cutting plate of the present disclosure is preferably realized insuch manner that the thickness of the running surface gradually variesfrom the outside to the inner side in a radial direction. Furthermorethe invention is more partiularly of importance for4 the kind of cuttingplate which is already known and in which the apertures of the runningsurface consists of slits extending from the inner to the outer edge. Inthis construction the material between the slits forms dams that aresupported at both sides, it is true, but these dams are readily liableto sagging owing to their comparatively great length. When making use ofthe invention this drawback is avoided.

A suitable practical construction of the cutting plate according to theinvention is obtained by giving the thickness of the running surface atthe inner edge a value of less than about 0.08 mm. for instance 0.06 mm.and at the outer edge a value of more than 0.08 mm., for instance 0.11mm.

Finally the use of the cutting plate according to the invention is ofparticular importance for those well-known shaving apparatus, in whichthe rotary cutting member is mounted with play both on the driving shaftand in the cutting head. In fact, it has been observed that such cuttingmembers tend to rock, and that during rotation the cutting member bearsin each instance solely on one and successively on a succeeding cuttingarm of the cutting member. This action" of the cutting member with theends of the cutting arms produces shock forces which often causedeterioration or bending of the cutting plate at the outer periphery.The invention sufficiently meets also this drawback.

The invention will be more fully explained by reference to theaccompanying drawings schematically representing one embodiment thereof.

Figure 1 represents half a section of a cutting plate according to theinvention and a cutting member cooperating therewith, Figure 2 being abottom view of this cutting plate.

Figure 3 is a side view in sectional elevation of the annular cuttingplate showing a stepwise variation of the axial thickness of the saidplate.

Figure 4 is still another side view in sectional elevation of thecutting plate showing a constant axial thicknes'sat one annular portionof the said plate and, aj'comparatively rapidly decreasing thickness atanother annular portion of the said plate.

Figure 5 is a further side view in sectional elevation of the cuttingplate showing a gradual radial increase in thickness' of the said plate.

Figure 6 is an additional-side view in sectional elevation of thecutting plate, with a flat top surface showing a decrease in'thicknessof the said plate at the inner side of the cutting head.

Referring to Figure 1, a cup-shaped cutting plate l is furnished with acentral recess 2 and a number of slits 3 which, as isA shown in Fig. 2,`extend radiallir (3') or substantially radially` (3"), but generallyfrom the central excavation to the outer edge. However, also otherapertures may be used such as those shown, for inf stance, at 3V. Theslits or apertures preferably open' in the central recess and in theouter wall of the "cutting plate. At the inner side of the cup-shapedcutting plate is provided an annular running surface 4 for a rotarycutting member 5. The running surface i is supported at the outer sideby the cylindrical outer wall and at the inner side bythe wall of thecentral recess which yields the required stiffness. According totheinvention the thickness of the running surface at the inner edge 6 issmaller than at the outer edgev 'l in such manner that the thickness ofthe material at 6 is smaller and at greater than the normal thicknesswhich is deemed admissible in the caseof a cutting plate having the samethickness throughout the active running surface. In-Fig. 1 use is madeof a gradually varying thickness. l

Figures 3 to 6 representstill other forms of construction. In Figure 3the decrease in thicknesstakes placeV stepwise. Figure 4 shows from theoutside to the inner side at first a constant thickness followed by a.comparatively rapidly decreasing thickness and then a constantthickness again. In Figure 5 use ismade of a gradual decrease inthickness atboth sides of the cutting plate and in Figure 6 solely adecrease in thickness Aof the'running surface has taken place at theinner side of the cutting head.

What we claimI is:

l. Dry shaving apparatus, comprising an annular cup-shaped cuttingplate'oand a rotary cut'- ting member, said platephaving an aperturedannular running surface for the said member, said plate being` axially',thinner at the inner portion of the said running surface than at theouter portion of the said surface.

2. Dry shaving apparatus, comprising an annular cup-shaped cutting platewith a central recess and arotary cutting finer-uber, said plate havingan apertured. .annular running surface for the said member, said plateaxially decreasing in thickness in a uniform manner from the outsideportion of the said surface to the inside portion of the said surface.

3. Dry shaving'apparatus, comprising an annular cup-shaped cutting plateand a rotary cutting member, said plate having an apertured annularrunning ysurface for the said member, said plate axially decreasing inthickness in a stepwise manner from the outside edge of the said surfaceto the inside edge of the said surface.

4. Dryshaving apparatus, comprising an annular cup-shaped `cutting platewith a central recess and a rotary cutting member, said plate having aradially apertured annular running surface for the saidmember, saidplate axially varying in thicknessfrom the inside edge of the saidsurface to the outside edge of the ,saidsurface.

5. Dry shaving apparatus, comprising an annular cup-shaped cutting platewith a central recess and a rotary cutting member, said plate having anannular running surface with substantially radial aperturesy for thesaid member, said plate being axially thicker at one annular portion ofthe said runningv surface than at another annular portion.

6. Dry shaving apparatus, comprising an annular cup-shaped cutting platewith a central recess and a rotary cutting mem-ber, said vplate havingan apertured annular. running surface for the said member, Vsaid platevbeing axially thicker at the outside edge of the running surface thanat the inside edge of thesaid. surface, the said cutting memberbeinggsupported at the edges of the said surface.

WILHELMUS LAMBERTUS LEONARDUS VIVIE. ALBERTUS VAN im LEE.

REFERENCES CITED The following referenceS. arcor record in the nie ofthis patent:

UNITED STATES PATENTS

